Installation and Operation Manual
RACE BOX
English
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Edition: Mar 2012
This manual is written for Nexus RaceBox 1.00
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1! Part specification ................................................................................................... 5!
2! Overview ................................................................................................................. 6!
2.1! Calculated Data .................................................................................................................. 7!
3! Installation .............................................................................................................. 8!
3.1! Mounting ............................................................................................................................. 8!
3.2! Serial / FDX Cable .............................................................................................................. 9!
3.3! Pushbutton ......................................................................................................................... 9!
3.4! Buzzer ................................................................................................................................ 9!
3.5! Software Configuration ..................................................................................................... 10!
3.6! Polar File .......................................................................................................................... 10!
3.7! Configuration File ............................................................................................................. 11!
3.8! Startup .............................................................................................................................. 11!
3.9! Shutdown ......................................................................................................................... 12!
4! Race Box Features and Their Use ...................................................................... 12!
4.1! Data Logging .................................................................................................................... 12!
4.2! NXB Log ........................................................................................................................... 13!
4.3! CSV Log ........................................................................................................................... 13!
4.4! Target & Polar Boat Speed .............................................................................................. 14!
4.4.1! Polar File .................................................................................................... 15!
4.4.2! Choosing Whether TBS or PBS is Sent to the Nexus Network .................. 15!
4.4.3! Displaying TBS and PBS in Other Fields ................................................... 16!
4.5! Set Steer Memory ............................................................................................................ 17!
4.6! Man Overboard (MOB) ..................................................................................................... 17!
4.7! Start Line Tactical Assistance .......................................................................................... 17!
4.8! In Sequence Data vs Out Of Sequence Data .................................................................. 18!
4.9! Configuring which data is sent to which fields .................................................................. 18!
4.10! Using the Race Box timer ............................................................................................... 20!
4.10.1! Starting the timer ...................................................................................... 20!
4.10.2! Syncing the timer ..................................................................................... 20!
5! Interpreting the data. What does it all mean? .................................................... 22!
5.1! How does the Race Box choose its target? ..................................................................... 22!
5.2! How does the Race Box choose the path to the target? .................................................. 23!
5.3! Distance and time to line calculations .............................................................................. 23!
5.4! Perpendicular Mode ......................................................................................................... 24!
5.4.1! Starting examples ...................................................................................... 24!
5.4.2! Reach in, reach out start ............................................................................ 24!
5.4.3! The Vanderbilt start .................................................................................... 24!
5.4.4! Other starting strategies ............................................................................. 25!
5.4.5! Connecting a GPS Receiver ...................................................................... 25!
5.5! Other Configuration Options ............................................................................................. 26!
5.5.1! Bow Location and Boat Length .................................................................. 26!
5.5.2! Position Data Source ................................................................................. 26!
5.6! Status Lights ..................................................................................................................... 27!
5.7! Data Damping .................................................................................................................. 27!
5.8! Error Conditions ............................................................................................................... 28!
6! AVAILABLE DATA FIELDS .................................................................................. 28!
6.1.1! BIAS – Starting line bias ............................................................................ 28!
6.1.2! PBS - Polar Boat Speed ............................................................................. 28!
6.1.3! TBS - Target Boat Speed ........................................................................... 29!
6.1.4! TTL - Time to start line in seconds ............................................................. 29!
6.1.5! TTB - Time to Burn ..................................................................................... 29!
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6.1.6! MTL - Meters to start line ........................................................................... 29!
6.1.7! FTL - Feet to start line ............................................................................... 29!
6.1.8! BL - Boat Lengths to start line ................................................................... 29!
6.1.9! OPT_A - The optimum apparent wind angle ............................................. 30!
6.1.10! OPT_T – The optimum true wind angle .................................................. 30!
7! Specifications ....................................................................................................... 39!
7.1! Technical specifications Compss Instrument ................................................................... 39!
8! Warranty ................................................................................................................ 39!
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1 Part specification
___________________________________________________________
Items delivered with the Race Box
Qty Description
1 The Race Box
1 push button
1 buzzer
1 DB9 male to DB9 female serial cable
1 power cable
1 SD memory card
4 Mounting screws
1 This manual
Registering this product
Once you have checked that you have all the listed parts, please take time to fill in the
warranty document and return it to your national distributor.
By returning the warranty card, it will assist your distributor to give you prompt and
expert attention. Keep your proof of purchase. Your details will also be added to our
customer database so that you automatically receive new product catalogues when
they are released.
Warranty conditions see 8.
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2 Overview
Thank you for purchasing the Nexus Race Box!
The Nexus Race Box is a great addition to any Nexus instrument system with an FDX
server. Our Race Box can calculate both polar and target boat speed (PBS & TBS), log
your instrument data in both Nexus native binary NXB format and comma separated
values (CSV) format and assist your tactician in making the best start possible. From
time to time, firmware upgrades will be released for the Race Box, and these can easily
be installed. Instructions for upgrading the firmware will be provided with each update.
Information generated by the Race Box is sent to Nexus instruments in accordance with
the Race Box configuration. This will be discussed in detail later in this manual, but in
general, you can send Race Box data to any NX2 or NXR instruments. This includes
the NX2 Multi, the Multi XL, the NXR Multi and the larger NXR instruments.
The Race Box is powered by 12 volts DC, just as the Nexus server is. A standard, DB9
male to DB9 female straight through serial cable connects the Race Box to the Server
data port.
To get the most out of your Race Box, you'll want to have a Nexus buzzer installed on
your FDX server and a Nexus push button connected to the Race Box. The Race Box
will provide the SET STEER and MOB functions you're used to, so you won't need an
additional button. In fact, with the Race Box, all these functions and more are controlled
with a single button. You can reuse the button that is currently connected to your server
if you have one.
The Race Box requires that a standard SD memory card be installed. This card will
have your polar table and your configuration file, both of which are read when the Race
Box starts up. Your log files will also be stored on this card. After your racing, you can
easily remove the card and use any computer with an SD card reader to review your
data.
The Race Box has four, full duplex RS-422 connections for communication with NMEA
0183 and other devices. Future firmware updates will allow the connection of some
peripherals to these connectors. In the initial release, you can connect a NMEA 0183
GPS receiver to the Race Box. The Race Box will accept the RMC sentence up to 5
times per second, for high speed position, COG and COG updates.
The Race Box also has three colored lights which can be seen through the translucent
case. These lights, referred to as the “status lights” or “status LEDs,” will be explained
in detail later in this manual.
Finally, the Race Box has connections for MOB, SET STEER and a buzzer. These are
for future use and currently are left unconnected.
How does it do all that?
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Fundamentally, all the Race Box does is accept data from the Nexus server, do some
processing on it and then sends the results to the Nexus server to be published on the
Nexus network. For the most part, this data is just displayed to the crew. In Classic and
NX2 series instruments, three special data fields exist which can hold calculated data.
These are TBS, CAD and CFD. TBS is a special field, and it is used only for speed
targets (more on this later). The NXR series supports these and ten additional fields,
referred to as CUSTOM0 through CUSTOM9. With the Race Box, the crew can
configure what information gets sent to each of these fields, within certain limitations.
For example, if the Race Box is calculating “time to line (TTL),” we have to tell it which
field to display this information in. If we have only NX2 instruments, then the choices
are CAD and CFD. With the NXR, we have ten additional choices.
So the primary method of giving the crew data while sailing is simply displaying the data
on the instruments. There are logs kept which can be viewed after you're done sailing.
The status lights also offer some information.
Once connected, data is received into the Race Box from the Nexus server. This is
done automatically. Also, there is a button that is used to control the Race Box and also
the Nexus server. This is used to tell the Race Box where the starting line begins and
ends, as well as to control some other features.
Like any computer, the not-so-old saying applies: Garbage in, garbage out. To get the
best information from the Race Box requires that your Nexus system be well calibrated
and that the crew understand how it works and what the numbers it is presenting mean.
This manual will explain all that for you and, if you have questions, you can contact
Nexus support.
2.1 Calculated Data
For a list of data fields that the Race Box can calculate, please refer to Appendix 'A'.
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3 Installation
• The installation includes 5 major steps:
1. Read the installation and operation manual.
2. Plan where to install the RaceBox.
3. Run the cables.
4. Install the RaceBox.
5. Learn the functions and setting up your system.
Before you begin drilling ... think about how you can make the installation as neat
and simple as your boat will allow. Plan where to position the transducer and
instrument. Think about leaving space for additional instruments in the future.
• A few ”do nots” you should consider:
− Do not cut the cables too short. Allow extra cable length at the RaceBox so
it can be disconnected for inspection without having to disconnect all
attached cables.
− Do not run cables in the bilge, where water can appear.
− Do not run cables close to fluorescent light sources, engine or radio
transmitting equipment to avoid electrical disturbances.
− Do not rush, take your time. A neat installation is easy to accomplish.
• The following material is needed:
Wire cutters and strippers.
Small and large Philips and a small flat head screw driver.
Hole saw to cut a hole for the instrument back of 63 mm (2½").
2.8mm drill for the RaceBox mounting screws
Plastic cable ties
If you are doubtful about the installation, obtain the services of an experienced
technician.
Installation
3.1 Mounting
First, find a suitable mounting location for the Race Box. Any location suitable for the
Nexus Server should serve equally well for the Race Box. You will notice that, just like
the Nexus server, the Race Box only has openings on one side. Also like the server, the
Race Box should be mounted so that it's bottom is against a vertical surface and the
side with the wire openings is oriented downward. This is so that any water which may
inadvertently splash on to the box is more likely to run off the box instead of into it. The
Race Box need not be mounted in close proximity to the server if this is your
preference, as long as you can connect a serial cable between the Race Box and the
Server.
Once you have located a suitable mounting location, use the four supplied mounting
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screws to mount the Race Box. You will beed to remove the outer lid to expose the
mounting holes. Once the Race Box is mounted, leave the outer lid removed until the
installation procedure is complete.
12VDC Power
Next, hook up power leads to the Race Box. The Race Box is powered by 12 Volts DC
and requires as much as approximately 0.17 amperes of current under certain
conditions (but typically uses much less). Please see the diagram in figure yyy to locate
the 12VDC connection terminal. You may connect the Race Box to the same power
switch/breaker as your Nexus server if you like. However, if you think you will want to
change your polar table during a day of racing without having to reset the rest of your
Nexus instrument system, then you will want to provide the Race Box with a dedicated
switch.
3.2 Serial / FDX Cable
The next step is to connect the supplied serial cable between the Nexus Server and the
Race Box. Be sure to tighten the thumb screws on the cable so that neither end falls out
while sailing. If the supplied cable does not reach, you can use any standard DB9 male
to DB9 female “straight through” cable such as can be bought at any computer store
and many other stores.
3.3 Pushbutton
Connecting a push button to the Race Box is optional, but if you do not connect one you
will not be able to use the timer and start line tactical functions of the Race Box.
We have supplied a weatherproof push button, but any normally open type push button
can be used. To connect the button, please refer to the diagram in figure yyy to locate
the proper screw terminals. When tightening the screws, please be careful not to over
tighten. Just make the connection finger tight, then verify that a firm tug on the wire
does not pull it from the terminal. If a firm tug does cause the wire to pull out, then
reconnect a bit more tightly.
If you are connecting your button to the Race Box only, then it does not matter which
side of the button is connected to which screw terminal. However, if your button is also
connected to an instrument such as a steer pilot, be sure that the button wire that is
connected to the ground side of your instrument is also connected to the ground
(negative) button terminal on your Race Box. Ideally, the button should be connected
only to the Race Box.
3.4 Buzzer
We strongly recommend that when the start line timing features of the Race Box are
used, that you have a loud buzzer installed on your Nexus Server. The buzzer is used
to generate an audio conformation that certain commands to the Race Box were
accepted correctly.
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Please refer to your Nexus Server manual for instructions on how to select and connect
a buzzer.
Done
You have now completed the hookup. Replace the outer lid and your installation is
complete.
3.5 Software Configuration
The Nexus Race Box is essentially a special purpose computer designed specifically to
interface with the Nexus instrument system. Because it is very feature rich and
powerful, it requires a bit more configuration than other Nexus products do. Don't worry
though, we will address everything you need to know both in this manual and on our
web site. You'll have your race box humming along in no time.
The Race Box accepts a standard SD memory card. This memory card can be written
to and read from using a standard personal computer running Windows or Linux and
also by a Mac. Many computers have a slot for reading SD cards already, but if your
computer does not you will need an SD card reader which plugs into your computers
USB port. These are available at many computer stores and also online. Reading files
from and writing files to this card is done exactly as you would read from or write to your
hard disk drive, your USB thumb drive and other similar memory peripherals.
3.6 Polar File
If you want the Race Box to generate either Target Boat Speed (TBS), Polar Boat
Speed (PBS) or both, you'll need to put your polar file on to the SD card. The difference
between PBS and TBS will be discussed later in this manual.
The polar file used by the Race Box uses the Nexus NXP polar format. This is the same
format used by the Nexus Race Software. Your polar files are typically supplied in a
number of formats, including NXP. If you bought your polar files from US Sailing, for
example, then you have them in NXP format. If you have your polar data in some other
format, please refer to Appendix 'D' for a description of the Nexus NXP polar format.
Polar files are just text data and you can easily edit another format to match NXP format
using a text editor such as Windows Notepad.
If you don't already have a polar file for your boat or if a polar file is not available, you
can make your own using log data from the Race Box. There are several web sites
dedicated to how to make polar files, and a little searching on the Internet will find a
wealth of information on making polar files.
Once you have your polar file ready, copy it to the SD card. You can name your polar
file whatever you like, but it must end in .NXP in order for the Race Box to recognize it.
Don't put more than one polar file on the card. The Race Box will use whichever it finds
first and you won't know which one it is using. If you have different polar files, perhaps
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for spinnaker and non-spinnaker racing, then store each polar file on a different SD
card. The easiest way to switch from one to the other will be to replace the SD card.
3.7 Configuration File
The Race Box has many different options and therefore requires a detailed
configuration file. Please refer to Appendix 'B' for a sample file. A default file was
included on your SD card. So that the Race Box can find it, the name of the
configuration file must be:
RP4N.CFG
The configuration file is a text file and the file name is not case sensitive. You can edit it
with a text file editor, such as notepad on Windows or TextEdit on a Mac, however you
should not edit it with a word processing program such as Microsoft Word. If you do
choose to edit it with a word processing program, be careful to make sure the file is
saved as a text file only. Do not save it in any other format, including RTF (rich text
format).
Each part of the configuration file will be explained as the features it controls are
discussed.
Finally, its very important to remember that you can not remove the SD card while the
Race Box is running, edit the config file, and replace it. The configuration file is only
read when the race box starts up. More important, removing the SD card while the
Race Box is running can corrupt the card's file system, erasing your data and possibly
even rendering the card completely unusable.
3.8 Startup
We're sure you anxious to get your Race Box to do something, so let's turn it on! Before
you power it up, put your polar file and a configuration file on to the SD card. If you do
not have a polar file, then use the default one supplied with the Race Box. With the
Race Box switched off, put the SD card in to the Race Box.
You can now power up your Race Box and Server. It is not important which is turned on
first. You may start the Server first, the Race Box first or both of them together.
Assuming everything is connected and installed correctly, you'll see the blue data light
on the Race Box come on. It will remain lit solid until the Server is powered on. As soon
as it begins getting data from the Server, it will be begin to flash steadily. Approximately
10 seconds later, it should begin flashing more rapidly and irregularly. This indicates
that the Race Box has successfully switched the Server into FDX mode and
communications are underway.
Occasionally, the Race Box will fail to switch the Server into FDX mode on the first try.
In this case, you will see the red error light come on briefly while the Race Box tries
again. Soon, the red light will go out and the blue data light will begin its irregular
flickering.
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Any time you see the blue data light flickering irregularly, you know that the Race Box
and the Server are communicating in FDX, and things are working correctly.
If you have not disabled logging in the configuration file, the Race Box has now opened
two log files. You can view these using a computer.
3.9 Shutdown
Shutdown procedure for the Race Box is easy enough. Just turn it off by removing
power to it. However, there is one very important caveat. Just as with a PC or Mac, an
SD card can not simply be removed from its socket. You must first “eject” it. On the
Race Box, we “eject it” by just turning off the Race Box. It is very important that you
never remove the SD card from the Race Box without first shutting down. If you do, it is
possible that you will corrupt the data on the SD card, rendering it corrupted and
possibly completely unusable.
After you shut off power to the Race Box, wait for all the lights (including the orange
power light) to be completely off before removing the SD card or restarting the Race
Box. The Race Box will not restart until it has completely powered down.
4 Race Box Features and Their Use
4.1 Data Logging
The simplest feature to use on the Race Box is data logging. The Race Box creates two
different types of logs. The first is the NXB log and the second is the CSV log. If you
have configured the race box to create either type of file, the Race Box will create the
log file each time it is turned on. The files will be named in sequence. The first log file
on the memory card will be named like this:
RACE_AAA.NXB
RACE_AAA.CSV
As you can see, each log file has an extension (the three character ending of the name)
which indicates what type of file it is. The log file names are selected in sequence.
Therefore, the next time the Race Box is started, it will see the files it already created
and create a new name, like this:
RACE_AAB.NXB
RACE_AAB.CSV
After that, they will be:
RACE_AAC.NXB
RACE_AAC.CSV
And so on until you get to ZZZ. At this point, you will have to erase some log files to
make room for more.
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4.2 NXB Log
The NXB log file is the Nexus native binary log in NXB format. This log is identical to the
logs generated by the Nexus Race software. In fact, you can transfer this log to a
computer and play back the sailing session in the race software. The race software will
work identically to how it would work if you had recorded the log using it in the first
place.
You can enable or disable this log by changing a setting in the config file. To enable this
log, ensure that the following line is in the Race Box configuration file:
NXB_LOG_FILE=ON
If you prefer that this log not be generated, then change the above line to:
NXB_LOG_FILE=OFF
4.3 CSV Log
The CSV log is a log of the data recorded, but not in binary form. This log is text data,
where each different field of text is separated by a comma. This is commonly referred to
as “comma separated values.” You can very easily import this data into another
program for analysis. Many programs, including small database programs, and
spreadsheets such as Excel or Open Office, are readily able to import this data.
Once its read in, you can perform any analysis you like. For example, you may wish to
use a spread sheet to create a chart which plots both target boat speed (TBS) and boat
speed (speed through water – STW) to see how well your crew maintained the correct
target boat speed. You may also wish to chart the true wind direction (TWD) to see
what type of shifts you experienced.
You can enable or disable this log by changing a setting in the config file. To enable this
log, ensure that the following line is in the Race Box configuration file:
CSV_LOG_FILE=ON
If you prefer that this log not be generated, then change the above line to:
CSV_LOG_FILE=OFF
In the case of the CSV file, you can control how frequently the Race Box adds a line of
data. The fastest logging rate is 5 seconds. You can set it to another value, such as 10
seconds, like this:
CSV_LOG_INTERVAL=10
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4.4 Target & Polar Boat Speed
The Race Box can calculate and present either Target Boat Speed (TBS), Polar Boat
Speed (PBS) or both.
Whats the Difference?
When a boat is sailing upwind, it can sail higher (decreasing its true wind angle) and
shortening the distance it needs to sail, but this causes it to sail more slowly, increasing
its travel time. Conversely, it can sail lower (increasing its true wind angle) which will
increase the distance the boat needs to sail but increase its speed. For any given True
Wind Speed (TWS), somewhere between zero degrees True Wind Angle (TWA) and 90
degrees TWA there is a sweet spot; a perfect TWA which is the optimum balance of
boat speed and distance.
This is also true downwind. Of course, all sail boats can sail with the wind exactly
behind them, dead down wind. But for almost all boats, its faster to gybe back and forth,
since your boat can reach faster than it sails down wind, even though this increases the
distance you need to sail. When sailing downwind, somewhere between 90 degrees
TWA and 180 degrees TWA, there is a TWA that produces the optimum combination of
boat speed and distance.
For any given true wind speed (TWS), these optimum TWAs change. When sailing at
the optimum TWA, your boat is traveling at a particular boat speed. This boat speed is
known as the Target Boat Speed (TBS). If you're actual boat speed is faster than your
target, you may want to head up to slow down but shorten your distance. If its slower,
you may want to head down to increase your distance but speed up.
If you choose to have the Race Box send Target Boat Speed to the Nexus TBS field
(more on this later), the Race Box will send the optimum TBS for the current wind
velocity. This means that if your TWA is less than 90 degrees (that is, you're sailing
upwind), the Race Box will send the upwind target that corresponds with the current
wind velocity. If your TWA is lower than 90 degrees, the optimum down wind TBS is
sent to the Nexus server.
Polar Boat Speed (PBS) is a simple concept. It is the speed at which your boat should
be traveling through the water given the current wind velocity and TWA. If you chose to
have PBS sent to the TBS field, The Race Box will send the speed at which your polar
table predicts you will be traveling given the existing TWA and TWS, even if the TWA is
above or below the optimum angle for these conditions.
Which one is better to use is a always a matter of an opinion and usually depends on a
variety of factors. Many people prefer to use TBS when racing a windward / leeward
course, while other courses may command PBS. Some drivers prefer to just write the
targets out on to the deck and send PBS to the instruments. There is no right or wrong
way to do it. You'll have to choose based upon your preferences.
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4.4.1 Polar File
To do this, the Race Box needs a “polar file.” A polar file is a list of boat speeds and
wind angles. These files can be generated by computer programs which know about a
boats hull shape, weight, rig dimensions and other factors. If you want to purchase a
polar file for your boat, contact US Sailing. There are also a lot of polar tables on
www.blur.se. Or, a polar file can be created by recording data about how a boat actually
performs at a variety of wind speeds and angles. The Race Box logs are a great way to
record this information.
Your polar file must be put on the Race Box SD card. As mentioned earlier, the polar
file should be in standard Nexus polar file format. The file name must end in .NXP and
the file must be placed on to the SD card so it can be read by the Race Box at startup.
If you don't have a polar table or just prefer not to use one, then set the following
configuration option in the rp4n.cfg file like this:
USE_POLAR_TABLE = N
When this is set, the Race Box will not try to load the polar file at startup, so no polar file
is necessary on the SD card. Also, it will not be able to calculate PBS or TBS
information.
TBS and PBS are both calculated by checking the true wind speed (TWS) and your
current true wind angle (TWA), and then applying this information to your polar table. Of
course, this information varies as the wind speed and your sailing angle does.
The data in polar files also needs to be adjusted for the height of your wind transducer
above the water surface. Many people manually edit the data in their polar file, but this
is not necessary since the Race Box will compensate for transducer height. In order for
it to do this, the configuration file needs to be told the height of the transducer above the
surface of the water, in feet. The proper line in the configuration file is:
WIND_XDUCER_HEIGHT=43
If you have already adjusted your polar file to compensate for your transducer height,
then set the height to 0, like this:
WIND_XDUCER_HEIGHT=0
4.4.2 Choosing Whether TBS or PBS is Sent to the Nexus Network
The Nexus instrument system has a data field called TBS, but this field can be used
either for target boat speed or polar boat speed. The Race Box configuration file
controls what information is sent to this field. This information is then published
throughout the Nexus network and all instrument features related to TBS can be used.
For example, all of the NX2 and NXR instruments have the ability to simply present the
value of the TBS filed, in knots, as a number. Also, the NX2 Wind Instrument can trim
on TBS. When the Wind Instrument is set up to do this, it has an indicator which raises
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when you are sailing above your target speed, and lowers when you are below it.
Similarly, the Multi XL has a trim feature which will tell you what percentage you are
below or above your target speed. NXR instruments have similar features.
You can control whether it is TBS or PBS which is sent to the Nexus network by
changing a setting in the Race Box configuration file. If you wish to send PBS to the
network, ensure that the following line is in the configuration file:
TBS_DATA=PBS
If you prefer that TBS be sent to the network, then change the above line to:
TBS_DATA=TBS
Be sure you do not have both lines in the file at the same time, unless of course one of
them is commented out.
4.4.3 Displaying TBS and PBS in Other Fields
If you like, you can also cause the value of both TBS and PBS to be displayed in other
fields. The Nexus system has “custom data fields” which can display certain types of
data. These are available on the NX2 instruments and the Multi XL instruments and
some of the NXR instruments. The NXR instruments have ten “custom data fields”
which can display other information. For example, they can display information from
load cells. We can tell the Race Box to send TBS and PBS to them for display. You
won't be able to use the trim percentage or other TBS specific functions, but you will be
able to see the target speed so you can compare it to your actual speed.
To do this, set the following lines in the configuration file:
CAD=PBS
CFD=TBS
These lines will cause polar boat speed to be sent to the CAD field and target boat
speed to be sent to the CFD field. To send data to the custom fields of the NXR series:
CUSTOM0=TBS
CUSTOM1=PBS
This will cause target boat speed to be sent to custom 0 while polar boat speed is sent
to custom 1. If you wish to send this data to different custom fields, simply change the
number after the word CUSTOM. Valid numbers are from 0 to 9.
Please refer to the manuals for your NX2 or NXR instruments to learn how to make
CAD, CFD and CUSTOM0 through CUSTOM9 display.
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4.5 Set Steer Memory
You can use the Set Steer, or wind memory, feature of your Nexus server by pressing
the button connected to your Race Box. You won't need an additional button connected
directly to your server.
To set the steer memory, press the button once for about a half a second and release it.
If there is a buzzer connected to your server, you will her one short beep. The steer
memory will be updated and your steer pilot instrument will function as expected.
4.6 Man Overboard (MOB)
You can use the man overboard function of your server by pressing the button
connected to your race box. You won't need an additional button connected directly to
your server.
To trigger a man overboard (MOB) condition, do five (5) consecutive short presses of
the button. Each short press should be about half a second long. The MOB function will
be triggered and your Nexus system will behave exactly as it would if the button were
connected directly to the server.
Also, the Race Box will write a text file to the SD card. This file will contain the position
and time that the MOB function was triggered.
4.7 Start Line Tactical Assistance
The Race Box is able to provide assistance to the crew before and during the starting
sequence by providing data about the starting line and your position relative to it. Using
the Race box, you can find out:
• Starting line bias relative to the true wind direction (BIAS)
• Your distance from the starting line in boat lengths, meters or feet (BL, MTL or FTL)
• The time required to reach the line on your current course and speed (TTL)
• The time you will be late or early to the line (time to burn – TTB)
In order to get this information from the Race Box, you need to tell the Race Box where
each end of the start line is. In order to get time to burn, you'll also need to tell the Race
Box when the starting sequence began (discussed more under Timer).
Pinging the Line
In order to tell the Race Box where the start line begins and ends, we approach each
end of the line with the boat's bow and press the button. The ends can be pinged in
either order. Also, if the race committee moves either end after you have pinged the
line, you need only re-ping the end that they moved.
To ping the right hand end of the line, slowly bring your boat's bow as close to the end
mark as you can before the PRO begins screaming and throws his or her coffee at you.
When your bow is as close as it can get, do two quick presses on the button. If you do it
correctly, the server buzzer will emit two short beeps. Also, the green info light on the
Race Box will begin flashing slowly.
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To ping the left hand end of the line, slowly bring your boat's bow as close to the pin as
you can. When your bow is as close as it can get, do three quick presses on the button.
If you do it correctly, the server buzzer will emit three short beeps and the info light on
the Race Box will light on solid.
If you ping the left hand end of the line first, the green info light will flash rapidly, then
light solid when you pine the right hand end.
At this point, the location of both ends of the starting line, as well as its compass
bearing, have been computed and stored in the Race Box's memory. We're now ready
to start!
4.8 In Sequence Data vs Out Of Sequence Data
As mentioned earlier, the Nexus system has a number of “custom fields” into which we
can send whatever data we like. The NX2 series, including the Multi XL instruments,
offers the CAD, CFD and TBS fields. TBS is only used for speed targets, so that leaves
us with just CAD and CFD. The NXR series offers ten additional fields, called custom 0
through custom 9.
The Race Box attempts to expand options by allowing the crew to configure it to send
certain data to a particular field while in the starting sequence, and other data to that
same field both before the starting sequence has begun and after the starting sequence
is complete. For example, we might display “Time To Burn – TTB” in the CFD field for
the period of time between when we started the timer and when the gun sounds. At the
gun, the CFD field will change and display optimum apparent wind angle.
Data which is sent to any particular field during a starting sequence is referred to as “in
sequence data” while data sent to any particular field before the start timer is started or
after the timer reaches zero is referred to as “out of sequence data.”
4.9 Configuring which data is sent to which fields
As discussed earlier in the overview, the Race Box primarily accepts data from the
Nexus server, performs various calculations on this data and sends the results back to
the Nexus server to be published on the Nexus network.
With one exception, the various fields in the Nexus network accept data and only
display it. The exception is the TBS field. Instruments can display the TBS sent to them
in knots, but also have special features which can show more information about TBS,
such as the percentage your current boat speed is above or below your current TBS.
Therefore, it only makes sense to send either TBS or PBS to the Nexus TBS field.
The Classic and NX2 instruments, including the Multi XL, can accept two additional
fields, called CAD and CFD. The CAD field can display values from 0 to 359 as whole
numbers. The CFD field can accept data from ? To ?, but with decimal
portions. Because of differences in how these fields display data, its better to send
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some data types to CAD and others to CFD.
Because they are represented as whole numbers, the best choices of data to send to
the CAD field are:
BL
OPT_A
OPT_T
The best choices to send to the CFD field are:
BIAS
TTB
TTL
The time fields will have a dot in the display, such as 3.40. In the case of the time fields,
this means 3 minutes and 40 seconds. In the case of an angle, such as bias, it
represents 3.40 degrees.
The NXR series instruments have the ten custom data fields, so any type of data
generated by the Race Box can be sent to any of those ten custom fields.
The Race Box is told which data to send to which field in its configuration file. Here is
an example from the config file:
CAD_IS=BL
CFD_IS=TTB
;
CAD_OS=OPT_T
CFD_OS=BIAS
The first line, CAD_IS=BL, means that the BL (boat length) data calculated by the Race
Box will be sent to the CAD field of the Nexus network while the starting sequence is in
progress. In short, CAD_IS means CAD field while in sequence. Likewise, CFD_IS
means CFD field while in sequence. Conversely, CAD_OS means CAD field while out
of sequence and CFD_OS means CFD field while out of sequence.
Therefore, before you begin the starting sequence and after the sequence ends, the
example above will cause the optimum true wind angle to be sent to the CAD field while
the start line bias will be sent to the CFD field. As soon as you trigger the start timer,
CAD will begin displaying boat lengths to line (BL) and CFD will begin displaying time to
burn (TTB).
If you prefer that no data be sent to a field, you can set it to “OFF” like this:
CFD_OS=OFF
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